Publications by authors named "Jimenez-Rivera C"

Article Synopsis
  • - Hepatorenal tyrosinemia type 1 (HT-1) is a rare genetic disorder caused by a deficiency in the enzyme fumaryl acetoacetate hydrolase, leading to toxic metabolite buildup that can harm the liver, kidneys, and nervous system.
  • - The introduction of the drug NTBC (nitisinone) has greatly enhanced HT-1 management when treatment begins early, alongside the importance of newborn screening for timely diagnosis.
  • - Patients require regular monitoring of liver and kidney function, and those who do not respond to treatment may need a liver transplant; they are also at risk for long-term neurocognitive issues, necessitating ongoing assessments and therapies.
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Metabolic-(non-alcoholic) associated fatty liver disease (MAFLD/NAFLD) has increasingly become a worldwide epidemic. It has been suggested that renaming NAFLD to MAFLD is critical in identifying patients with advanced fibrosis and poor cardiovascular outcomes. There are concerns that the progression to non-alcoholic steatohepatitis (NASH) may become a constant drive in the future healthcare of children and adolescents.

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Background And Aims: Alagille syndrome (ALGS) is characterized by chronic cholestasis with associated pruritus and extrahepatic anomalies. Maralixibat, an ileal bile acid transporter inhibitor, is an approved pharmacologic therapy for cholestatic pruritus in ALGS. Since long-term placebo-controlled studies are not feasible or ethical in children with rare diseases, a novel approach was taken comparing 6-year outcomes from maralixibat trials with an aligned and harmonized natural history cohort from the G lobal AL agille A lliance (GALA) study.

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  • - A patient with infantile-onset Crohn's disease showed some initial improvement with corticosteroids, but their condition worsened when the medication was tapered off, prompting the switch to a monoclonal antibody treatment.
  • - Infliximab, the first monoclonal antibody used, was metabolized quickly, leading to the development of antibodies before the third dose was given; this caused a need for a different medication.
  • - Adalimumab was started and showed a good clinical response, but it also cleared quickly, necessitating higher doses to maintain effectiveness; monitoring drug levels can help prevent loss of response in young children.
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Unlabelled: Fontan-Associated Liver Disease (FALD) is a common extracardiac complication seen in patients following the Fontan procedure. There are no consensus guidelines on screening and management of children with FALD.

Objective: The current study aims to determine academic pediatric hepatologists' practices and identify variability in management provided to children with FALD in Canada.

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Background & Aims: Bile salt export pump (BSEP) deficiency frequently necessitates liver transplantation in childhood. In contrast to two predicted protein truncating mutations (PPTMs), homozygous p.D482G or p.

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  • Alagille syndrome (ALGS) is a complex disorder primarily affecting the liver, and this study investigated the long-term liver health of affected children through a large, international sample.
  • The study included 1,433 children diagnosed with ALGS across 67 medical centers in 29 countries, revealing that only about 40% reached adulthood with their native liver intact.
  • Elevated total bilirubin levels in infants are linked to significantly increased risks of developing severe liver-related problems, which can help doctors in making treatment decisions and evaluating therapies for ALGS patients.
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  • The brain's ability to handle novelty stimulates curiosity and exploration, which may influence sensitivity to cocaine.
  • Key brain areas involved in exploring new environments include the locus coeruleus (LC), the ventral tegmental area (VTA), and the hippocampus.
  • The study found that exposure to novel environments affects the activity of VTA dopamine neurons, suggesting the LC plays a significant role in regulating dopamine responses even after cocaine exposure.
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Objectives: Kawasaki disease (KD) is an immune-mediated vasculitis of childhood with multi-organ inflammation. We determined the risk of subsequent immune-mediated inflammatory disease (IMID), including arthritis, type 1 diabetes, IBD, autoimmune liver disease, primary sclerosing cholangitis and multiple sclerosis.

Methods: We conducted a matched population-based cohort study using health administrative data from Ontario, Canada.

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The hyperpolarization-activated cation current (I) is a determinant of intrinsic excitability in various cells, including dopaminergic neurons (DA) of the ventral tegmental area (VTA). In contrast to other cellular conductances, I is activated by hyperpolarization negative to -55 mV and activating I produces a time-dependent depolarizing current. Our laboratory demonstrated that cocaine sensitization, a chronic cocaine behavioral model, significantly reduces I amplitude in VTA DA neurons.

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Objective: Kawasaki disease (KD) is a childhood vasculitis with conflicting reported North American trends in incidence and patient characteristics.

Objectives: (1) determine KD incidence between 1995 and 2017; (2) compare patient characteristics by era and age group; (3) determine complication and cardiovascular follow-up rates.

Methods: We used population-based health administrative data to identify children (0-18 yr) hospitalized with KD in Ontario, Canada between 1995 and 2017.

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Background And Aims: Mutations in ATPase phospholipid transporting 8B1 (ATP8B1) can lead to familial intrahepatic cholestasis type 1 (FIC1) deficiency, or progressive familial intrahepatic cholestasis type 1. The rarity of FIC1 deficiency has largely prevented a detailed analysis of its natural history, effects of predicted protein truncating mutations (PPTMs), and possible associations of serum bile acid (sBA) concentrations and surgical biliary diversion (SBD) with long-term outcome. We aimed to provide insights by using the largest genetically defined cohort of patients with FIC1 deficiency to date.

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Midbrain dopamine neurons communicate signals of reward anticipation and attribution of salience. This capacity is distorted in heroin or cocaine abuse or in conditions such as human mania. A shared characteristic among rodent models of these behavioral disorders is that dopamine neurons in these animals acquired a small size and manifest an augmented spontaneous and burst activity.

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De novo PTAID may develop in pediatric solid organ transplant recipients, have a diverse spectrum, and are occasionally treatment resistant. Previous reports showed resolution of immune cytopenias in solid organ transplant recipients following replacement of the calcineurin inhibitor tacrolimus with the mTOR inhibitor sirolimus. Herein we describe a retrospective review (2000-2017) of subjects who developed PTAID in whom immunosuppression was changed to sirolimus.

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The ventral tegmental area (VTA) plays an important role in the reward and motivational processes that facilitate the development of drug addiction. Presynaptic α1-AR activation modulates glutamate and Gamma-aminobutyric acid (GABA) release. This work elucidates the role of VTA presynaptic α1-ARs and their modulation on glutamatergic and GABAergic neurotransmission during cocaine sensitization.

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Article Synopsis
  • Biliary atresia (BA) is a leading cause of liver transplants in children, and this study evaluated the health care costs associated with BA in Ontario, Canada, compared to healthy controls.
  • The findings showed that children with BA incur significantly higher annual health care costs ($4,210) than controls ($283), with costs increasing further for those who needed liver transplants.
  • There was no significant correlation found between the age at which surgery (heptoportoenterostomy) was performed and the direct costs incurred; however, older age at surgery (≥90 days) was linked to a much higher risk of needing a liver transplant.
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The I is a mixed depolarizing current present in neurons which, upon activation by hyperpolarization, modulates neuronal excitability in the mesocorticolimbic (MCL) system, an area which regulates emotions such as pleasure, reward, and motivation. Its biophysical properties are determined by HCN protein expression profiles, specifically HCN subunits 1-4. Previously, we reported that cocaine-induced behavioral sensitization increases HCN2 protein expression in all MCL areas with the Ventral Tegmental Area (VTA) showing the most significant increase.

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Chronic cocaine exposure produces enduring neuroadaptations in the brain's reward system. Persistence of early cocaine-evoked neuroadaptations in the ventral tegmental area (VTA) is necessary for later synaptic alterations in the nucleus accumbens (NAc), suggesting a temporal sequence of neuroplastic changes between these two areas. However, the molecular nature of the signal that mediates this sequential event is unknown.

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In this study, electrochemical impedance spectroscopy was used for the first time to study the adsorption of dopamine in carbon fiber microelectrodes. In order to show a proof-of-concept, static and dynamic measurements were taken at potentials ranging from -0.4 to 0.

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Background: Non- Alcoholic Fatty Liver (NAFL) is a spectrum of liver diseases (LD) that ranges from benign fatty infiltration of the liver to cirrhosis and hepatic failure. Hepatic ultrasound (US) and serum alanine aminotransferase (ALT) are often used as markers of NAFL. Our aim is to describe prevalence of NAFL and associated findings on ultrasound (US) and biochemical parameters in a population of children and adolescents with obesity at the Children's Hospital of Eastern Ontario.

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Background & Aims: Adult studies of autoimmune hepatitis (AIH) have shown that the model of end-stage liver disease is associated with resistance to first-line treatment. Using a multicentre retrospective database, we sought to determine if the paediatric end-stage liver disease (PELD) score would similarly predict treatment resistance in paediatric AIH.

Methods: One hundred and seventy-one children from 13 Canadian centres who fulfilled the International Autoimmune Hepatitis Group (IAIHG) criteria were included and assessed for change to second-line therapy within 24 months of primary treatment onset.

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Background: The Canadian 4-year native liver survival rate for biliary atresia (BA) after Kasai Portoenterostomy (KP) is 39%. The Canadian Biliary Atresia Registry (CBAR) was used to examine variability of surgical and medical management of BA.

Methods: Gastroenterologists and surgeons in all 14 Canadian pediatric tertiary centers were invited to complete an online survey of their BA management practices.

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Unlabelled: The progressive escalation of psychomotor responses that results from repeated cocaine administration is termed sensitization. This phenomenon alters the intrinsic properties of dopamine (DA) neurons from the ventral tegmental area (VTA), leading to enhanced dopaminergic transmission in the mesocorticolimbic network. The mechanisms underlying this augmented excitation are nonetheless poorly understood.

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